OE Pressure relief prevents fuel vapors from exiting the fuel system under normal operating conditions. This allows an escape path for pressure in the event of an impact situation where the fuel tank has collapsed. It also permits pressure to escape if the vapor management system malfunctions.

OE Vacuum relief prevents fuel vapors from exiting the fuel system via the fill tube under normal operations. This allows an alternative path for air to flow into the tank if there is an obstructi